During the Imperial Era, the Protectors maintained a base on Concord Dawn's third moon in order defend the system. In 3 BBY, following a dogfight with the Rebels' Phoenix Squadron, Rau met with an Imperial officer that gave him credits as promised in their agreement. Rau also informed the officer of his encounter with a Rebel squadron and the officer told Rau to notify him if the rebels return.
During this time, the base was infiltrated by two rebels, Jedi Kanan Jarrus and Sabine Wren. As Jarrus spoke with Rau about him saving his and Master Depa Billaba's life during the Third Battle of Mygeeto, Wren then planted explosives on the Fang fighters. However, several of the Protectors found Wren and assumed she was a bounty hunter. Wren, as a member of House Vizsla's Clan Wren, demanded a duel with Rau in accordance to the Mandalorian code. Rau then agreed to it, despite Jarrus telling Sabine that this was not what Hera wanted. However, Sabine then set off the charges and destroyed most of the Fang fighters. Rau and his protectors then attempted to capture the rebels, but the rebels escaped and Rau was taken prisoner by the Rebels. Due to his status, Rau then told his protectors to allow the Rebels passage through the system and not to mention his capture to the Empire.